CD14 and knee injury: This mirrors previous findings that CD14+CD16− monocytes are the main precursors of osteoclasts in rheumatoid arthritis [83], that their proportion in synovial fluid is predictive of the Knee Injury and Osteoarthritis Outcome Score (KOOS) [84], and that CD14 monocytes play an important role in OA aggravation through inflammatory cytokine secretion [85].